The present invention relates to support assemblies for aboveground structures, and more particularly to support assemblies for aboveground pipelines including a support saddle and apparatus associated with the support structure to prevent damage to the pipeline upon seismic or other major disturbances that can dislocate the pipeline relative to its aboveground supports.
The most economical means for transporting crude oil or other petroleum products through Arctic regions is a pipeline. Normally such pipelines are subterranean, that is, they are installed in back filled trenches that interconnect one or more pumping stations between a well and a shipping terminal or refinery. Through certain Arctic regions, however, a subterranean pipeline is not feasible as the permafrost that constitutes the soil will not, under certain termperature conditions, support the weigt of a buried pipeline. Since the oil or petroleum traveling through the pipeline has an average temperature that resides above 32.degree. F, the heat of the oil in the pipeline combined with atmospheric heat during the summer months will melt the permafrost and destroy its supporting qualities, thus allowing the pipeline to move or sag within the ground and potentially causing damage to the pipeline. The solution to this problem has been to place portions of the pipeline above the ground.
Not only are pipelines generally not supported above the ground because of the additional cost involved in constructing an aboveground pipeline, but Arctic conditions, especially those that exist between the north slope of Alaska and the southern coast of Alaska, present problems that have heretofore been unencountered in the construction of a pipeline. First of all, vertical support members or pilings must generally be oriented perpendicularly to the plane of the horizon, that is vertically, so as to achieve maximum strength with minimum structure and cost. The topography over which the pipeline traverses dictates that the pipeline at any given support location will not always be oriented at the same height and angulation as at the previous or the succeeding support location. To design individual interconnecting assemblies for the pipeline and the vertical support members that could individually accommodate the varying orientation would be very expensive.
Moreover, in any Arctic areas, the pipeline must traverse regions in which seismic disturbances are likely to occur. A seismic disturbance could easily cause a shift in the ground and thus the pipeline support structures over a portion of the pipeline route. This in turn could cause the pipeline support structures for a portion of the pipeline to shift relative to adjacent support structures. If the support structures and the pipe were rigidly connected, such a shift might impress undue stress on the pipeline, causing damage to the line and potentially rupturing the line, resulting in an undesirable spill of crude oil.
It is, therefore, a broad object of the present invention to provide a support assembly for interconnecting a pipeline with an aboveground support member to eliminate the need for many individually designed and constructed support structures and to minimize the labor and time required to install the support structures and the pipeline. Further objects of the present invention are to provide an interconnecting structure that is easily fabricated, that is inexpensive to construct, that can be permanently affixed to the pipeline and to the ground support member.
An additional broad object of the invention is to provide an aboveground support structure that will minimize or eliminate damage to the pipeline and the ground support member should a differential force be applied therebetween, as might be caused by a seismic disturbance. Additional objects of the present invention are to provide a support assembly that has provision for allowing relative movement between the pipeline and the ground support structure, and to provide such an assembly that will not move upon occurrence of a minor disturbance but that will react to major disturbances.